Manufacture of metal packing-rings



F. RAY.

MANUFACTURE OF METAL PACKING RINGS.

AP PLlCATl0N Fl LED MARI. 4 1918- V Patented Mar. 2, 1920.

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Application filed March Q1918. Serial No. 220,353.

To all QUILOWL it may concern:

Be it known that I, Fnnnnmon RAY, a citizen of the United States, residing at Short Hills, Essex county, State of New Jersey, have invented certain new and useful Improvements in the Manufacture of Metal Packing-Rings, of which the followisa specification.

My invention relates to methods of making piston rings and the like and may also be used for correcting piston rings that have been improperly treated or hammered. More particularly my method has for its object to produce a piston ring from which a portion has been cut out, due to the thickness of the saw in splitting, or from which a substantial portion has been out out to make a lap joint which is then rolled to give it a new circular shape of decreased diameterand which is subsequently so treated that it will exert a uniform outward radial pres sure. This ring is of the kind in which the radial pressure is due to the elasticity of the metal of the ring and not to external springs.

l Vith the above and other objects in View, the invention may be said to consist of the method hereinafter described and more particularly pointed. out in the claims.

Referring now to the drawings:

Figure 1 is a plan View of the blank before cutting I Fig. 2 is a similar View or the blank after cutting;

Fig. 3 is a side elevation of cutting, looking at the cut;

Fig. l is a plan View of the blank after rolling; I

, Fig. -5 is a side elevation of the blank after rolling, looking at the out;

Fig. 6 is a plan view of the blank after hammering Fig. 7 is a side elevation of the blank after hammering, looking at the out; and I Fig. 8 is a diagrammatic View of the bending rolls with the blank in a position to be acted upon.

Fig. 9 is a perspective View of the joint.

In making a piston ring in accordance the blank after with my invention, I may, preferably do; first produce an annulus oicast iron or other suitable metal which iscirculagupon. the outside and which may or may not be of the same cross-section throughout, de'. pending upon the type of ring desired. Furtl'ierinore, the outside diameter of this blank preferably is larger than the diameter. of the bore of the cylinder in which it is to be used. This excess in diameter of the blank is predetermined, so that the circumference of the blank will be sufiiciently great to permit a section to be removed, sufliciently large to make the lap joint, after the removal ofwhicli and after final completion of the ring the circumference of the ring will still be equal to the circumference of the cylinder bore, exceeding it only by the small amount allowedv for finishing the ring. In the particular mode of carrying out the invention l'iere. described; I now divide the an nulus or ring blank, by means of milling cutters, one cutter. cutting a .slot shown on the upper side of the ring in Fig. 3, the other cutter cuttingthe; slot shown on the lower side of Fig. 3. These two missus stantiallyintersect at their inner corners, so

that the metal of the ring is or may be sep arated at these points.

T .i. of my process. By means of this rolling step I reduce the ring to ion new circular form of decreased diameter and place the ring in a condition so that a. stress moment will not exist in any part of it. l aocomp ish the rolling step by passing the ring blank through a, set of bending rolls consisting of three or more oils one or more of which are adjustable. properly adjusting the position of these rolls the curvature of every part of the section of the ring blank shown in Fig.2 can'be altered to assume the curve.- ture of the ring blank shown in Fig. t; thus the blank shown in 2 will be substantially circular at its outside circumference 7 and l1kewise the blank 1n the state shown in Fig. 4- will also be substantially circular at its outside surface, but the'diameter of the blank'in the state shown in Fig. a will be less than that shown in 2 By rolling the ring the metal of the whole ring is distorted and permanently set, so that the radius of curvature at every point is permanently changed from ithat of the larger to that or the smaller ring, and the ring with its new, fixed radius of curvature remains in this condition without the existence of a stress moment at any point.

After rolling, the blank .is then in the condition to be distorted along its internal circumference and may be hammered on its internal circumference by means of the haminer used for such purposes or may be then subject the ring .to the rolling step gin knurled by means of the machine shown in my copendin patent application Serial No. 103,795, filed june 15, 1916, now PatentNumher 1,304,371, and the action of hammering or nurling may be determined by means of the gage disclosed in my eopending pat ent application, Serial No. 93,90al, filed April 27, 1916, until the ring gives uniform radial pressure at all points of its c1reumference. r

' -By this means the correct law of the. cam is obtained and predetermined so that the I ring produced by thehammering or nurl Ill ing machine will exert a uniform radial reaction or pressure at all points on the c1rcumference. Or I may make use of the predetermined law, for nurling' or hammering the rings set forth in my allowed co-pending application, Serial Number 257,843, filed October 12, 1918, wherein the law ofhammering is given as one in which the intensities-of the hammer blows are so varied that the intensity of the blow at any point is proportional to unity minus the cosine of the angle between the split of the rin and the point which is being hammered, p us a constant.

By hammering the blank which has been subjected to the rolling process, and. left in the usual manner.

It will be observed that my improved method has many advantages over the ordinary method of making rings by cutting out a portion and springing or compressing the resultant cut-out ring into a circle of smaller diameter. In such prior methods, in order to obtain material fo1 the lap joint or to allow for the material removed by the splitting'tool, the ring blank is made larger than the finished size ring desired. The piece is then cut out to make the lap joint, and the rim compressed or sprung into the cylinder, which is of smaller diameter than that of the original uncut ring. If, however, the cut blank is sprung into the cylinder, it follows that a stress moment will be set up which will be uniform at ever point of the circumference of the ring. his is contrary to the desired effect, for in order that there may be uniform radial pressure at all points of the circumference of the ring it is necessary to have not a uniform but a -varying stress moment at every section of the ring and the radius of curvature of the ring when unconfined should change at every point along one-half of the ring blank.

Furthermore, as the ends oi the ring are approached, the stress moment should ap proach zero as a limit, in order to obtain uniform radial pressure around the ring, Consequently, it follows that, if the blank of Fig. 2 is sprung into the shape shown in Fig. 4, instead of the stress moment approaching zero at the ends of the ring, the stress moment-is as large at the ends as in any other section. Since hammering the interior cir cumference of the ring does not decrease the stress moment at any section but can only increase it, it follows that it would be impossible to obtain a zero bending moment at the-ends of the ring, by merely-cutting out a piece and springing the' ring into a chuck or cylinder and subsequently hammering it. For even at the ends, the stress moment, due to springing the blank into the chuck or holder, would remain.

By my method of rolling the ring, however, all these objectionsare done away with and the correct law of stress moments and the corresponding correct law .of varying radii of curvature for difierent parts of the ring may be imparted to the ring by hammering, even though a portion of it has been cut out to form the lap joint or a portion removed in splitting.

My invention is also applicable to correct' ing rings improperly hammered, for by sub ecting the rings to my rolling step I take ut'the stresses introduced by the hammering and bend the ring into circular formof the desired diameter, 'leavin it in an unstressed condition. I then ammer it according to a predetermined law and put the desired uniform radial pressure into the ring. The construction and operation of my invention will be clear from the above description and drawings.

What I claim as new' and desire to secure by Letters Patent is: 1. The method of treating metal packing rings. which consists in producing an annular blank, removing a portion of the blank and permanently altering the curvature of the blank so that the ends will approach each other to form a joint and the blank be reduced to a smaller circular form.

2. The method of makin metal packing rings which consists in pro ucing an annular blank,-rem0ving a portion thereof, rolling the cut blank so as to alter its curvatureand give it a circular form of smaller diameter and hammering the resultant circular ringthus produced with blows of varymg intensity. l

The method of making metal packing rings which consistsiin producing a ring blank, slotting the sameat two places so as to form a lap joint, rolling the cut blank so as to alter its curvature and give it a circular form of smaller diameter, and subjecting the resultant circular ring to an operation which introduces stress moments varying in the different sections of the ring.

4. The method of making metal packing rings which consists in producing a ring blank, dividing the same, rolling the divided blank so as to alter its curvature and give it .a circular form of smaller diameter, and subjecting the resultant circular ring to an operation which introduces stress moments Varying in the diiferent sections of the ring.

5, A step in the manufacture of metal packing rings which consists in eliminating stress in an open ring by subjecting the same to a rolling process so as to permanentlv distort the metal and so as to compel the ring to take the desired shape, leaving all portions of it free from stress moments.

6. The method of correcting rings improperly hammered which consists in eliminating stress in the open ringby subjecting it to a rolling process so as to permanently distort the metal-and to compel the ring to take the desired shape, and then hammerin the ring in accordance with a predetermined law so as to put the desired uniform radial pressure into the ring.

7. The method of correctin rings improperly hammered which consists in eliminating stress in the open ring by subjecting it to a ,rolling process so as to permanently distort the metal and to compel the ring to take the desired shape, and thenldistorting the ring along its internal circumference in accordance with a predetermined law so as to put the desired uniform radial pressure into the ring.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing Witnesses.

FREDERICK RAY. Witnesses W. F. Bissino, J. W. RENITZF 

